Starting device for electric motors.



H. H. LEE & A. E. BUTTON.

STARTING DEVICE FOR ELECTRIC MOTORS.

APPLIOATION FILED 00T.27,1908.

963,160. Patented July 5,1910;

Fig.1. 3 L a INSZEZSZ'TUES.

HARRY H LEE. ARNULZ? E. BUTTUN.

JTTY

.iiinvoLo E. Bu'r'rox, citizens of the United .btates. residing at Schenectady, county of -Schenectady, State of New York, have in- UNITED STATES PATENT OFFICE.

HARRY H. LEE AND ARNOLD E. BUTTON, OF SCHENEOTADY, NEW YORK, ASSIGNORS TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

STARTING DEVICE FOR ELECTRIC MOTORS. I

Specification of'Letters Patent.

Patented July 5, 1910.

Application filed october 27, 1908. Serial No. 459,706.

To all whom it may concern:

Be it known that we, HARRY .H. LEE and vented certain new and useful Improvements 1n Starting Devices for Electric Motors, of

which-the following is a specification.

,This'invention relates to means for controlling electric motor circuits and has for its object the provision of a device whereby an'electric motor may be started and brought to 'running speed in a safe and etlicient manner.

Our invention relates more specifically to the starting'of alternating current motors of the induction type. In starting induction motors of the slip ring type, it is essential that -the secondary circuit be closed through the necessary resistances before the closing of the primary circuit. In carrying out our invention, therefore, we provide in connection with a hand operated device for cutting the resistance out of the secondary circuit, means whereby the primary circuit cannot be closed until all of the resistance is in series with the secondary of the motor. -We also provide means whereby the member which controls the secondary resistance cannot be left in an intermediate position, so as to burn out the starting resistance.

In the accompanying drawing, in winch we haveshown our invention embodied in The primary is arranged to be connected with the three phase mains 1, 2 and 3, by means of two electromagnetic switches 4 and 5, phase 1 being directly connected with the. windings of the motor. The secondary of the motor is provided with starting resistances 6, 7 and 8, one in series with each phase of the motor. These resistances are provided with contact studs arranged in a circle. The controlling member 9 which conslsts of three arms, one for each section of resistance, is pivoted at 9 and provided with a handle 10 on one arm, so that the member will move the three arms to vary the three resistances of the secondary circuit simultaneously. In the off position, the contact segment 10 is arranged to be engaged.- by the arm of the member on which the handle is mounted. A contact stud 12 is arranged adjacent the segment 11 and is connected therewith by means of the resistance v 12. The handle 10 is provided with a switch consisting of a plunger 13, normally pressed upward by means of the spring 11 but adapted to be engaged by the hand of the operator and pressed into engagement with the segment 11, to close the circuit of the contactors 4 and 5. The end of the segment 11 is offset upward, asshown at 15, so that when the arm reaches the end of its travels, the plunger will remain in engagement with the segment. Two-overload relays, 16 and 17, provided with bridging contacts 18 and 19, are

arranged in series with two primary windings and adapted to openthe circuit of the conhurtors i and upon overload.

The arrangement of circuits and modeof operation are as follows: lVhen the switch 20 is closed, the handle 10 is grasped by the operator and moved into engagement with stud 12, the plunger 13 being pressed downward so as to engage the stud. A circuit is then completed as follows: from phase 1, across bridging contactors 18 and 19, through the coils of contactors 4t and 5 in parallel, stud 12, arm 9 and conductor 21 back to phase 2. The contactors 4; and 5 are thus energized and the primary circuit closed. By moving the member 9 in a clockwise direction with the plunger 13 forced downward, the resistances 6, 7 and'S are cut out of the secondary circuit in a well-known manner. lVhen the running position is reached, that is, when the resistance is all cut out of the secondary circuit, the circuit of the contactors 4i and 5 will be kept closed by the engagement of theplunger 13 with the oifset'15 of the segment 11. As soon as the plunger 13 moves off the stud 12 in starting,the resistance 12' is connected in series with the coils of the contactors 4 and 5, thus reducing the current through these coils to such an extent that they will not operate but will be sufficiently energized to remain closed. Upon failure of voltage the contactors 4 and 5 will open the primary Circuit. In order to again close the contactors, however, the member '9 must be brought back to starting position in order to eliminate the resistance 12 and increase 7 said resistance,

the current from a holding to an actuating current. Upon the occurrence of overload,- the contactors will be deenergized by the voperation. of the relays 16 and 17.

While we have shown our invention embodied in concrete mechanism and as operating in a definite "manner in accordance with the patent statutes, it is to be understood that we do not limit our invention thereto, since various modifications will suggest themselves to those skilled in the art,

- without departing from the spirit of our in- 'vention, the scope of the annexed claims. I

/Vhat we claim as new and desire to secure by Letters Patent of the United States, lS,''

l. The combination with an alternating current motor, of means for starting the same comprising a primary circuit closing device, a resistance for the secondary circuit, a controlling member arranged to vary a normally open switch in connection with said member for completing the circuit of-the primary circuit closing device, said switch being arranged to be closed by the operator and held closed during the starting of the motor,-and means for securing said switch in closed position when the motor is brought to running position.

2. The combination with an alternating current motor, of means for starting the same. comprising an electromagnetic switch for closing the primary circuit, a resistance for the secondary circuit, acontrolling member arranged to vary the same, a normally open switch in connection therewith arranged to be closed by the operator in the starting position to energize the electromagnetic switch, a resistance for reducing the energizing current of the electromagnetic switch to a holding current When the member is moved from starting position and means for securing said switch in closed position when the .member reaches running position.

which is set forth in 3. The combination with a polyphase in- I duction motor, of means for starting 'the same comprising a resistance having a sectionfor each motor phase, a controlling member arranged to simultaneously vary the sectional resistances, a normally open switch in connection with said -member arranged to be closed by the operator to close the primary circuit during thestarting of the motor, and means for securing said switch in closed position when the member is in running position.

4. Thegcornbination with apolyphase in-. duction motor, of means for starting the same comprising a plurality of electromagnetic switches for closing the primary circuit, a resistance for each motor phase of the secondary circuit, a controlling'member arranged to simultaneously vary said re sistance, a normally open switch in connection with said member controlling said electromagnetic switches, and a resistance ar ranged to reduce the energizing current of said electromagnetic switches to a holding current when the member is moved from startin position.

5. T e combination with a polyphase induction motor, of means for starting the same comprising a plurality of electromagnetic switches for closing the primary cir- V cuit, a resistance for each motor phase of the secondary circuit. a controlling member arranged to simultaneously vary said resistance, a normally open switch in connection with said member arranged to be closed by the operator to energize said electromagnetic switches in the starting position, a resistance arranged to be connected in circuit with said electromagnetic switches to reduce the energizing current to a holding current when the member is moved from the starting position, and means for securing said switch in the closed position when the member reaches running position.

In witness whereof, we have hereunto set our hands this 26th day of October,'l908.

HARRY H. LEE.

ARNOLD E.- BUTTON.

lVitnesses:

HELEN Onronn, BENJAMIN B. HULL. 

